Control apparatus



Nov. 15, 1927.

A. H. CAN DEE CONTROL APPARATUS 7 Filed May 11. 1921 I I I 1 I/,

- INVENTOR Andrewfi'andee,

ATTORNEY Patented Nov. 15 1927.

UNITED STATES ANDREW -H. GANDEE, F FOREST HILLS,

HOUSE ELECTRIC & MANUFACTURING COMPANY, A

VANIA.

PENNSYLVANIA, ASSIGNOR T0 WESTING- GORPOBA TION OF IPENNSYIF common APPARATUS.

\ Application filed May 11, 1921. Serial No. 468,714.---

My invention relates to devices adapted 7 to rupture an electric are when formed between two points, such as contact members of unit switches for controlling electric motors or the like. The object of my invention is to provide a blow-out magnetof improved characterwhich will confine the path of an arc substantially within definite limits.

In the design of magnetic switches or .con' tactors, it is customary to provide an arc shield of insulating material and a single blow-out coil having magnetic pole pieces to direct the electricarc away from parts of the contactor or adjacent apparatus which might otherwise be injured thereby.

It is well understood that the extreme heat from an electric arc will, in the course of a I short time, disintegrate the arc chute at points'against which the arc is directed.

I propose to provide a substantial arcing horn of suitable current-conducting material for connecting the stationary contact member to one end of the blow-out magnet coil. Current traversing the convolutions of the blow-out coil is reversed in its direction through the arcing horn, with relation to the direction of the current through the adjacent convolutions of the coil. The magnetic field induced by the current traversing the arcing horn has lines of magnetic force which are opposed to those induced in the field between the blow-out-coil pole pieces.

By a suitable arrangement or relation of these fields, it is possible to control the path of an electric arc and, incidentally, to avoid deterioration of the arc shield.

The single figure of the drawing'is a side view, partially in section and partially in 40'elevation, .of apparatus embodying myinvention.

The engagement of stationary contact member '1 and movable contact member 2 is controlled by the switch plunger 3. An

arcing horn 4 is attached, at one end, to the stationary contact member 1 and is fastened at its other end to the blow-out coil 5. The other end of the blow-out coil is fastened to a bracket 6 mounted on an insulating base 7 which supports the entire switch structure. The blow-out coil is-provided with acore 8 and pole pieces 9 engaging therewith. All arcing horn 10 is attached to contact member 2. An arc chute 11, of well known design,

is provided.

X It may be assumed that the-contactor has been closed and that the current traversing the contact members.v 1 and 2 is directed from the bracket 6, in a direction indicated by the arrows,'through the blow-out coil 5. The current leaving the blow-out coil is directed through the arcing horn 4 and contact members 1 and 2. Upon interruption of the electrical circuit by the separation of contact members 1 and 2, the current traversing saidmembers is directed through the are which acts as a conductor and which behaves in the magnetic field of the blow-out magnet in a manner similar to an armature conductor in the magnetic field 'of .a motor. The path of the arc is bowed and extends, as indicated by the dotted arrow line,-from the arcing horn 4 to the movable contact member 2. The magnetic lines of force in the field between the pole pieces 9 are directed perpendicularly to the plane of the p'aper 'assuming' that the pole pieces lie in, planes parallel to the plane of the paper. The magnetic field, induced by current in the arcing horn 4, comprises lines of magnetic force encircling the arcing horn in a clockwise direction with respect to the direction of the current, that is to say, lines of magnetic force are directed downwardly at the left and along the upper extension of the arcing horn. At the intersection of these oppositely directed fields is a neutral zone. The path of the arc is extended outwardly to the left and upwardly under the influence of the field induced by the magnetic blow-out, but the upward movement 7 of the arc is opposed by the field induced 1 around the arcing horn and beyond the neutral zone. the two fields restricts the path of the arc and protects the upper section ot the arc chute. g

The length of the path of the are depends upon the ener in theinterrupted circuit. The lower arcing born 10, acting as a conductor, induces a magnetic field opposlte'to The combined action of' the field of-the arcing horn 4:. The arc is:

- directed away from the lower section or the arc chute, under the influence of that porthe pole pieces 9,

tion of the field not afiected by the field r .105

I Theadvantages of the structure which I v carried by the electromagnet and extending adjacent the sides of the chute, said pole pieces being disposed to'efiect themovement of an arc outwardly along the arc horns, one of the arc horns extending beyond the pole pieces and being adapted to serve as a feed conductor for the corresponding contact member to develop. a magnetic field in opposition to the electromagnet to restrict the travel of an arc along said are horn, thereby to protect the chute. 4

2. An arc-rupturing device comprising, in combination, a plurality of contact members, are horns carried by the contact members, an arc chute substantially enclosing the arc horns, an electromagnet and pole pieces carried by the electromagnet and extending adjacent the sides of the chute, said pole pieces being disposed to efiect the movement of an 1 are outwardly along the arc horns, one of the arc horns being extended beyond the pole pieces and adapted toserve as a feed conductor for the corresponding contact member to develop a magnetic field in opposition to the electromagnet at a point adjacent the pole ieces, thereby to limit'the travel ofan are a ong the arc horn.

3. An arc-rupturing device comprising, in combination, a. plurality of contact members, are horns carried by the contact members, an arc chute substantially enclosing the arc horns, an electromagnet and ole pieces carried by the electromagnet and extending ad- 'acent the sides of the chute, said pole pieces ing disposed to effect themovement of an arc outwardly along the arc horns, one of the arc horns being extending beyond the pole pieces and adapted to serve as a feed conductor for the correspondin contact member to develop a magnetic fiel in opposition to the electromagnet to create a neutral point between the two magnetic fields at a point near the ole pieces to restrict the travel of the are a ong said are horn .v

4; An arc-rupturing device comprising, in combination, a plurality of contact members, are horns carried by the contact members, an arc chute substantially enclosing the arc horns, an electromagnet and pole pieces carried by the electromagnet and extending adjacent the sidesof the chute, said pole pieces being disposedto efiecttlie movement of an arc outwardly along the arc horns, one of thearc horns being extended beyond the pole pieces and adapted to serve as a feed conductor for the corresponding contact member to develop a magnetic field in opposition to the electromagnet to create a neutral point between the two magnetic fields at a point near the ole pieces to restrict the travel of the are a 011g said are horn, said are how being extended back on itself from substantially the pointof the neutralized magnetic fields.

5, An arc-rupturing device comprising, in combination, a plurality of contact members, are horns carried by the contact members, an arc chute substantially enclosing the arc horns, an electromagnet and pole pieces carried by the electromagnet and extending adjacent the sides of the chute, said pole pieces being disposed to effect the movement of an arc outwardly along the arc horns, one of the arc horns being extended beyond the pole pieces, the outer end of the 'horn' being curved back on itself and connected to a feed conductor, thereby 'to provide for the development of a magnetic field in opposition to the electromagnet at a point near the pole I pieces to restrict the travel of the are along the arc horn. 6. An arc-rupturing device comprising, in combination, a plurality of contact \inemb'ers, arc horns carried by the contact members, an arc chute substantially enclosing the arc horns, an electromagnet and ole pieces carried by the electromagnet and extending ad- 'acent the sides of the chute; said pole pieces eing disposed to effect the movement of an arc outwardly along the arc horns, one of the arc horns being extended beyond the pole pieces, the outer end of the horn being curr ed back on itself and connected to a feed conductor to provide for the development of a magnetic field in opposition to the electro- -magnet at a point near the pole pieces and substantially where the arc horn begins to recede, thereby to restrict the travel of an are along the are born.

In testimony whereoflI have hereunto subscribed my name this 29th day of April,

ANDREW H. CANDEE. 

